The use of mobile communication devices has increased in recent decades. At first mobile phones were used extensively for making voice calls. As technology has developed and made mobile high bandwidth data communication possible, the use of mobile devices for data transfer has increased to such extent that mobile data transfer may be even more common than voice calls. The use of modern data services, including email and social media, often require almost continuous connection to networks. The users of user terminals may have enabled the user terminals to connect to Internet on their own without active user intervention.
The mobile communication devices communicate with communications networks using radio frequency transmissions. The effect of electromagnetic radio frequency radiation on users has been studied in recent years but no conclusive results on the harmful effects have yet been discovered. All radio communication devices must fulfil government issued safety criteria regarding radiation properties. However, users of the devices may want to monitor radiation exposure themselves.